Air-cooling machine



2 sheets-Sheet 1.

(No Model.)

wovModel.) 2 Sheets-Sheet 2.

'JfPpav o. GQBURNHAM. AIR COOLING MACHINE.

No. 246,073. Patented ug. 23,1881.

@/QWW NA PETERS, Pnalo-ulnegmphr, washington. D. t;

UNITED STATES .JOHN P. BURNHAM AND OLIVER Gr.

PATENT OEETCE.

BURNHAM, OF CHICAGO, ILLINOIS.

AIR-COOLING MACHINE.

SPECIFICATION forming part of Letters Patent No. 246,073, dated August 23, 1881.

Application filed May G, 1881.

To all whom t may concern:

Be it known that we, JOHN P. BURNHAM and OLIVER` G. BURNHAM, both of Chicago, in thc State oflllinois, have invented certain new and useful Improvements in AirOoolingMachines5 and we do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to single-chambered machines for cooling air and other similar fluids by the method of successive compression and expansion thereof.

It is a fault in a class ot machines for cooling air by compression and expansion that the heat developed by compression ot' the air is abstracted from a considerable part of the airbody subsequently to its compression. As a result, there is a tendency to expansion in the air being compressed, which adds to the resistance opposingthe compressingforce, or, in other words, which makes agreater power necessary to drive the machine. To remedy this fault machines of another class have been devised,in which sprays of water are injected into the compressin g-chamber durin gthe actof compression. This method obviously produces a moisture in the air which it is difficult to remove, and which for many purposes is highly objectionable. f

Another fault common in machines of this general class, which have but a single chamber, is that the air is expanded in contact with the same surfaces upon which it is compressed and cooled. In consequence, a considerable part of the heat abstracted from the air while it is under pressure is returned thereto while itis being expanded, and in so far the eifectiveness and economy ofthe machine are impaired.

As primary objects-of our present invention herein set forth, we seek, iirst, by purely mechanical means and in a single chamber, to simultaneously compress the air and abstract its heat; and, second, to expand the air in contact with other surfaces than those through which the cooling agent operates while it is being compressed.

Further objects of our invention are to provide in a sin gle-chambered machine such a con- (No model.)

struction as will, in the expansion of the air, recover very largely the power expended in its compression; to dispense with valves at the openings ofthe expansion-space, and generally to produce a. machine more simple in its construction and economical in its operation` while not less effective in its results, than the machines heretofore in use for cooling air by the method mentioned.

To these ends our invention consists in the several novel features ot' construction and operation and in the several combinations of devices hereinafter described and claimed.

Figure l of the drawings is a central vertical section ot' our machine. Fig. 2 is an elevation thereof, and Figs. 3 and et are fragmentary views, intended to show certain positions of the moving parts by which compression and expansion are successively effected.

H is the single chamber containing the working parts. Said chamber is here shown as being inclosed by the shell A B, of which A is a cylinder, open at the top and bottom and supported on the frame F, and B is an extension ot' A, cylindrical for a lower portion ot' its length, and havingits upperand principal portio'n conical and closed at the top.

C is a water-tank surrounding the part B of the shell described. Said tank is provided with an inlet, C', at the bottom and an outlet, C2, at the top, by which the water of the tank may be constantly changed as it becomes heated.

Within the cylindre-conical chamber H two moving parts effect the induction, the compression, the expansion, and the expulsion of the air. One ot' these is a piston, I), which works in the cylinder A, and the other isa cylindroconical plunger, L, fitted to the upper interior of the chamber H, and having its lower or cylindric portion ot' less diameter than the cylinder A.

K is an expansion-packing, ofleather or other suitable material, applied about the lower margin of the plunger and adapted by its contraction to allow air from above the plunger to pass downward about the same at this point when the plunger rises, but by its expansion to prevent its passage upward when the plunger falls.

VV V are valves in the upper end of the s hell A B, arranged to open downward and to close by springs s, and Ais a'lateral opening in the cylinderA, leading out ofthe chamber H. The piston P has long.bearing-surface, and closes the outlet A', except wheny at the bottom of its stroke. The piston I? andv plunger L described are driven out of time in the manner and by the means next described.

S is a drive-shaft mounted in pillow-blocks F, and provided with a heavy drive-pulley and balance-wheel, G. Said shaft is also provided at its extremity with the eccentric gearwheel E, having acrank-pin, I. A pitman, J, connects this crank-pin with the piston I),-as clearly shown in Fig. 1. Beneath the shaft S the shaft S is mounted in suitable bearings, carry ing the eccentric gear-wheel E', which has an equal number of cogs with E, meshes therewith, and is driven thereby. A long cran k-pin, l', projects from the wheel E', (being suitably braced to give strength, as shown in Fig. 2,) to the extremity of which is attached the pitman J. This pitman similarly connects with the arm R on the rod L of the plunger L, and is of such length as to carry the plunger in its upstroke to the top of the chamber H, as seen in Fig. 1. The relative movements of the plunger and piston will be understood from the sectional Figs. 1, 3, ande, wherein it will be rst notced that the crankpin I is set somewhat in advance of the pin I', so that the changes of direction of movement by the piston are made before those of the plunger. Otherwise the parts are connected so that the plunger and piston proximate at the beginning of the upstroke of the plunger at a point in the cylinder A about opposite which the center of the outlet A is located. From this point upward they continue near together until the piston has completed its upstroke-say opposite the top of the cylinder A. Here the plungerleaves the piston and rises to the top ofthe chamber H, while the piston reverses its motion and is brought nearly half its stroke downward, as seen in Fig. 1, before the plunger begins to follow. The lowest positions of the plunger and piston'are shown by dotted lines in Fig. 1. The unequal lengths of the pitmen J and J', as shown, contribute to give a nearly uniform upward speed of the piston and plunger from their positions shown in Fig. 3 to those shown in Fig. 4, and also increase the rapidity of the separation of these parts in their downstroke.

In the descent of the plunger from its highest position (shown in Fig. 1) it is plain -that the check-valves Vrwill be opened inward and air admitted above the plunger. In Fig. 3 the plunger is at rest at the bottom of its stroke, the space above it is filled with air just admitted, and the springfvalv'es have automatically closed. As the plunger and piston subsequently rise together the body of air referred to is compressed, the compression thereof being substantially completed on the termination of the pistons upstrolre. At this time the air stands above and about the plunger, exposed in a thin bodyA to contact with the cooling-surface of the shell B, embraced within the water of tank C, as seen in Fig. 4t. When the plunger here leaves the piston to complete its upstroke-the air passes downward past the packing K into the space between the adjacent faces ofthe plunger and piston. Thus it will be noted that as the air, while under severe compression, is confined within cooling-surfaces, to which it is exposed in a thin body, the generation and abstraction of heat are practically simultaneous, and that therefore little or no tendency to expansion from increased temperature can be present to augment the resistance tothe compressing force of the machine. When the plunger has forced the compressed air from above and around to beneath itself, as above described, or, in other words, when the plunger has reached the end i of its upstroke, the piston has commenced to move rapidly downward, producing a space above it and Within the cylinder A, in which the air is expanded. The proportions of the parts are preferably so contrived as to make this space equal to the original volume of uncompressed air admitted less its reduction by lowered temperature, when the top ofthe piston reaches the top of the outlet A', so that said air is expelled under normal pressure of one atmosphere. The air is forced out through the passage A mainly by the plunger in its further descent, and in small part by the piston, which rises to meet or proximate the plunger at a point about opposite the center of said outlet, as before stated, and as shown in Fig. 1.

It will again be noted that while the compression and cooling are effected within the shell B, the expansion is accomplished in the cylinder A. There is therefore no possibility of returning to the air in its expansion any appreciable part of the heat taken therefrom, as would be the case were the expansion and conipression effected wholly or in considerable part within the cooling-walls B.

In order to more effectively cool the air in the act of compression, the plunger L and its rod L are iliade hollow, as indicated in Fig. 1, the rod being continued to the bottom of the plunger. A current of water is maintained through said plunger by means of the following devices The plunger-rod L may be a tube, having inserted therein a central diaphragm, m, dividing said tube into two passages, Zand l, which are continued through the lateral arms L3 L3, projecting from the tubular rod near its top. The inlet to the interior of the plunger is here shown to be the passage I, which opens at t', near the bottom of the plunger, and the outlet is shown to be l', which opens within the plunger, near the top, at o. Flexible tubes L4, one of them connected with a source of watersupply and the other directed to a proper point of discharge, are continuations of the passages IOO IIO

may also be made oi' a series ofshort cylin-` l and L', and permitthe constant change ofthe water within the plunger while fthe latter is .in

motion. The rod L issteadied above the arm B by the guide-frame D, and runs in a suitable stuffing-box, L2, in the top of the shelly B.

As a result of the construction described, wherein the compression and expansionofthe air are effected in one and the same chamber and against the same piston, no loss of power is suffered by friction in the passage of the air through narrow and valved apertures usually employed in this class of machines. So, also, by the direct connection of the parts, as shown, in addition to the feature of a singlechambe-r mentioned, the entire expansive force of the air, after the abstraction of its heat, is available as a compensation for that expended in` its compression. The piston l? operating, as described, to open and close the outletA, no valves are required at this point, and the trouble and inconvenience fromfreezing and other causes attending the use otl such valvesare Wholly obviated.

The plunger L may be a cylinder for its entire length, working within avcylindric shell, B, of larger size; but such construction would not be so effective as the conical form of these vparts shown, because a less proportion of the air above said cylinder would be exposed to the cooling-surface, and the tendency to expansion in the air being compressed would not, therefore, be so effectively counteracted asili the construction shown. The plunger ders, successively narrowing toward the top, like a conc pulley, running within a correspondingly-formed shell, B; but such form of shell and plunger would be open to the same objection as the wholly cylndric form mentioned. Moreover, in either of these suggested forms a much larger body of compressed air would remain about the plunger than in the form shown, preventing the quick action ot'the valves V. y

The plunger` may be conical for a greater part of its length than is shown in the drawings, or wholly conical; but there is an advantage in the cylindro-conical forms here given it-namely, to thereby confine the air admitted above the cylinder more completely within the cooling-shell B in the act ot' compressing it.

Itmay be added that but for the purpose of recovering, through the expansion of the air, power expended in its compression, the piston l) might be dispensed with and a practical cooler would still remain. In this case the expansible packing K might be made to yield only to such pressure from above as would give the desired compression to the air above the plunger; or, instead of the expansible packing K as a means of releasing the com pressed air, an annular enlargement may be provided in the chamber H, above the lower margin ot' whichv the bottom of the plunger will be carried near the completion of its up stroke, into which enlargement the air would be first compressed, and from which it would be inally released, both by the upstroke of the plunger. These elements, therefore, may without the piston .constitute an operative mechanism.

i We do not wish to limit ourselves to the eccentricgear-wheels E and E as means of giving the requisite movements to the plunger and pisto'n, as cams orcranks actuated by other arrangements ot' eccentric gears may be employed for this purpose; nor is it essential to our invention that the plunger and piston have the precise relative movements in all respects as herein at length described. These gears have advantages of perfect certainty of action and ofallowing a high speed, itrequired, which, with their less cost, makes them desirable. There are advantages in the conical or tapered form ot' plunger and its inclosing shell that would appear it' said plunger and shell were combined with other features of construction in air-cooling and air-compressing mechanism than those here shown. Thus by this form ofthe parts nam edit is obviously practicable to move the plunger without friction ofsurfacc contact, and at the same 'time to wholly exclude` the air from its apex and about its sides. This form of plunger and shell will be useful in apparatus for merely compressing air for power purposes, the plunger being rigidly connected with the piston, (with a space between them,) and the conical shell heilig attached to the piston-cylinder in extension thereof.

Ve claim as our inventionl. In an air-cooling machine, the shell inclosing the chamber H, providedwith an inletvalve, V, and a suitable outlet, the surrounding cooler, and the reciprocating plungersmaller than and arranged within the shell, combined with each other and with suitable actuating mechanism, substantially as described, whereby air is admitted at the valve V, is compressed and cooled about the plunger, and is discharged at the end of the plunger opposite 'that at which it is admitted, as set forth.

2. In an air-cooling machine, the shellA B, inclosing a chamber, H, having a valved inlet and an outlet passage suitably arranged, combined with the piston I? and plunger L, and with actuating mechanism, whereby the piston and plunger are given differential movement within the chamber, substantially as and ior the purposes set forth.

3. In the air-cooler described, wherein the air is compressed about the plunger and is passed from one end to thc other thereof, the valved shell A B, having its upper portion conical or tapering, combined with the plunger of corresponding' form, substantially as described, and for the purposes stated.

4. In the air-cooler described, wherein the air is compressed and passes about the plunger from one end to the other thereof, the plunger L, made hollow and provided with a rod, L', having passages l and l', connected as IOO -plunger and piston are differentially impelled,

substantially as described. Y 6. In the air-cooling lnachine described, th cylinder A, having the outlet A', combined with the elongated piston P, arranged to open and close saidontlet,substantiallyasdescribed.

7. In an air-cooling or air-compressing machine, the conical or tapering plunger L, combined with the valved shell B, ot' form corresponding with the plunger, and having an extension, A, ot' uniform diameter, substantially as described.

In testimony that we claim the foregoing as our invention we affix our signatures in presence of two witnesses.

JOHN P. BURNHAM. OLIVER G. BURNHAM.

Witnesses M. E. DAYTON, JEssE Cox, Jr. 

